Damage Assessment of Struck Ships in Collision

Abstract

118 cases of ship collision accidents were surveyed in the records of Japan marine courts, for the purpose of assessing the damage state of the struck ships. Hayashi's quantification theory type I was applied to the damage assessment. The damage grades were expressed as 1 to 5 points in accordance with the descriptive words of the damage. Predictive damage grades as criterion variables were obtained in five classes of struck ships which were classified in terms of the gross tonnage. Here the ratio of mass of a striking ship to that of a struck ship and the striking speed were selected as the main items of the cause to damage grade.The results obtained are as follows : (1) The present damage assessment is verified to lie on a significant level by an analysis of variance, for the collision cases of struck ships below M class (below 699 G. T.).(2) The category scores of the items used in the quantification theory indicate that a striking speed has a great influence on actual collision damage, as is predicted by an equation of the kinetic energy lost in the collision.(3) Fuzzy reasoning approach can be useful for linguistic evaluations pertaining to structural damage under special conditions of collision.